It is common for most fireplaces to have a relatively small viewing area as compared to the fireplace frame that is exposed to a view. For example, many fireplaces include a glass panel or doors through which the internal cavity (or combustion chamber) is viewed, as well as vents and louvers above and below the glass and exposed framing around several sides of the glass. As a result, only about 30 to 50% of the total front surface area of the fireplace is glass or otherwise provides viewing of the combustion chamber. Because the non-glass features of the fireplace front cover such a large percentage of the fireplace front surface, the combustion chamber itself must often be significantly reduced in size in order for the fireplace to be sized for a given fireplace application.
One primary reason why the glass portion of a fireplace front surface is restricted in size is because of the clearance required below the combustion chamber to house the fireplace controls. Typically, a fireplace includes controls for the heat source, such as a valve for a gas burner or a thermostat for electric heat source, and those controls are positioned beneath the combustion chamber with access to that space being provided by a removable panel or an access cover positioned below the fireplace glass.
Another reason why the glass portion of a fireplace front surface is restricted in size is to provide space for a blower and air plenum system that are typically at least partially positioned beneath the combustion chamber. Typically, cool room air is drawn into the plenum by the blowers through a vent/louver at a bottom portion of the fireplace front, the air is heated within the plenum from heat emanating from the combustion chamber, and the heated air is exhausted out from the plenum with the blower through a vent/louver at a top portion of the fireplace front. The plenum and associated vents/louvers require space and framing that may otherwise be available for the combustion chamber and the fireplace glass.
A further disadvantage of many known fireplaces is that the airflow into the combustion chamber for purposes of combustion is often restricted. Due to the space requirements of the plenum system and controls, the passages used for directing combustion air into the combustion chamber are relatively small and natural movement of air through these passages may be difficult. Restricted flow of combustion air often results in a diminished flame size and sometimes less efficient combustion of the fuel.
A fireplace that addresses these and other disadvantages of known fireplaces would be an important advance in this technical field.